Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Caribou ME
951 am EST Sat Feb 6 2016
high pressure will briefly crest over the region this morning
before moving east this afternoon. A weak are of low pressure will
pass north of the state late tonight and will send a cold front
across the region Sunday morning. Low pressure will pass south of
the area Monday with another area of low pressure to pass south of
the region Tuesday.
Near term /through tonight/...
944 am update...the remnants of an old shortwave are spreading middle
and high clouds across the region this afternoon. Temperatures
will continue to moderate through the day and tonight ahead of a
more vigorous shortwave that will cross early Sunday. The concern
with this feature will be an Arctic cold front that has strong
potential to set off a line of snow squalls in northern zones
Sunday morning...weakening as it moves south in the afternoon.
surface high pressure crests over the area this morning and moves east
during the day. A weak area of low pressure or clipper system is
evident on satellite pictures across Ontario early this morning.
The low will deepen a bit today into tonight passing well north of
the area tonight. The models have trended a bit further north with
the track of the low compared to 24 hours ago. The cold front
associated with the low will move into far northwest Maine by around 09z
and quickly sweep into central portions of the County Warning Area by 12z sun.
Clouds will quickly increase today with some flurries or light snow
possible this afternoon across northern and western portions of
the County Warning Area. Highs will be about 5 degrees above average and this
will range from the low to middle 20s in the Saint John valley to to
near the freezing mark downeast. A period of weak overrunning snow
is possible this evening, mainly for northern areas with any snow
accumulate to be under an inch. As the cold front pushes into northwest Maine
after midnight it will likely be accompanied by a band of snow
showers, but the greatest instability is expected just beyond the near
term. The clouds and some wind will keep temperatures relatively mild
tonight with lows mostly in the 20s, with some teens in the far northwest
toward daybreak as the cold front races through.
Short term /Sunday through Monday/...
low pressure will skirt by to our north Sunday, dragging its
attendant cold front across the Pine Tree state. This will be a
rather sharp front with rapid cooling after its passage. Guidance
continues to indicate there will be decent instability along the
front as lapse rates will exceed 7 c/km. As such, expect snow
squalls will be possible, as shown by the latest snow squall
parameter values. Any squalls would be capable of producing near-
white out conditions, strong wind gusts to 40 miles per hour or more, and a
quick inch of snow accumulation. Gusty west winds will follow the
front as well, ushering in a much colder airmass. Temperatures
will top out around 20 across northern Maine as daytime highs will
be early, but the Central Highlands down through Bangor to the
coast will peak in the middle 30s as the front will pass through
these areas later in the day. Skies will clear out behind the
front as well. Sunday night will be cold, with much of northern
Maine dropping below zero, while more southern locations will
remain in the positive single digits.
Lots of uncertainty for the next system which will begin to approach
late in the day Monday. The forecast models are having a tough time
agreeing on this system, both model-to-model as well as run-to-run.
The overall trend, though, has been to shift the storm and its
precipitation further south and east, away from shore. In fact, the
latest GFS and European model (ecmwf) runs give even coastal downeast little to no
precipitation through 7pm Monday. However, given the lack of model
agreement and the fact that it seems there has been a middle-term
southeast bias lately...have kept at least chance probability of precipitation for
accumulating snow across downeast Maine. Monday's highs will range
from the teens in the north to the middle 20s downeast.
Long term /Monday night through Friday/...
as mentioned above, there's lots of uncertainty as we head into
the middle of next week. While there's at least some consensus
that there will be a digging upper trough across the eastern
conus, there's little agreement between models on what happens
with the numerous shortwaves that will be rotating around this
trough. At this time, there's a potential system looks to affect
our forecast area sometime Tuesday- Wednesday, though exact
details on where, when, and what sort of impacts are not clear.
Some poorly defined waves look to follow over the next day or two,
with our area to mainly stay dry. The upper trough will finally
shift east of US by the end of the week, followed by a bitterly
Aviation /15z Saturday through Wednesday/...
near term: VFR with conditions to lower to MVFR late in the day or
during the evening at the northern taf sites from khul to kfve.
Predominately MVFR at the northern sites tonight, but with a period
of IFR possible in light snow. VFR expected at kbhb and kbgr
Short term: MVFR conditions will prevail at the northern sites
Sunday morning while the southern sites will be VFR. A cold front
will move from north to south during the day, along with possible
IFR conditions in snow showers and squalls. Once this GOES by, VFR
conditions will prevail at all terminals as skies clear. VFR
conditions should continue through a good part of Monday, though
MVFR ceilings will become more likely late Monday and especially
Monday night and Tuesday, mainly at the southern sites, as snow
lifts northward from passing low pressure. Some improvement is
possible Wednesday as snow should come to an end, but a low cloud
deck should remain.
near term: have lowered the Gale Warning to a Small Craft Advisory
for the coastal waters and have dropped the Small Craft Advisory
for the intra-coastal waters, but have issued a new Small Craft
Advisory starting this evening. There will likely be a brief lull
in the wind and seas today on the coastal waters with conditions
briefly below Small Craft Advisory levels, but the period appears to be short
Short term: winds and waves will gradually subside through the
day Sunday as high pressure briefly builds over the region.
However, strong low pressure will cross south of the waters,
resulting in increasing winds and seas Sunday night and Monday.
Gale-strength winds are likely to develop either late Sunday night
or early Monday, so additional headlines may be needed.
Marine...Small Craft Advisory from 7 PM this evening to 7 am EST Sunday
Small Craft Advisory until 7 am EST Sunday for anz050-051.